This question involves wireless, but I think it is fundamentally one of switching.
I manage the network in a large college residence hall. At present, the resident rooms are connected through wired connections to 2 6509s (sup2 layer 2 only).
Each 6509 is configured for three vlans which are trunked to a 2960G-24TC-L located in a central wiring closet where the six are trunked together on out to campus.
We are rolling out a wireless network that will involve approx 20 aps connetcted to each 6509. We will be using a WLC 4402 (2 gig ports)to manage the wirless and this is located in the central closet with the 2960G-24TC-L .
Because we have extra fiber runs from each 6509 to the central wiring closet, I can connect the WLC directly to each of the 6509s and thereby localize the traffic between the ap's and the WLC. Allowing the 6509s to do the "heavy lifting" here appeals to me as it distributes the load between several devices.
On the other hand, simply adding the vlan carrying the traffic between the ap's and the wlc to the existing trunk ports between the 6509s and the 2960G and then connecting the WLC to the 2960G has the appeal of simplicity.
So the crux of the question would be whether I would see an decline in perfomance, or any other downside, by adding the traffic between the WLC and 40 ap's with up to 450 wireless clients to the load on the 2960G (forwarding rate 35.7 mpps)